***
Watched his last video. Would have liked to have seen the PCB removed so we could see the switch contacts. I suspect it just uses the single PTC and some transistors for the clamp. Maybe a TVS in there. I doubt it would do very well in my transient testing.
Joe, I added the high resolution photos on the video's description, including the rotary switch.
As you imagined, it is an ordinary meter in terms of safety and rotary switch design.
The UT139C that I am still editing is much more promising. I know you tested it up to 5.1kV, which to me is quite impressive (similar to the much more expensive Keysight U1231A)
Does it ever become stable? Those are some big jumps.
The leads will add capacitance. Seen some that will read zero with the leads installed, like that Yokogawa for example. Just depends on the meter.
Joe, I added the high resolution photos on the video's description, including the rotary switch.
As you imagined, it is an ordinary meter in terms of safety and rotary switch design.
The UT139C that I am still editing is much more promising. I know you tested it up to 5.1kV, which to me is quite impressive (similar to the much more expensive Keysight U1231A)Thanks for adding them. Looks like the same old problems we have come to expect. The UT139C didn't make it as far in the transient tests as the Amprobe AM510, which is a bit strange as both are UNI-T products. Still, it's more robust than most of their products and AT LEAST it survived that little grill starter that seems to be famous for damaging them. The difference I see between the 139C and the 510 is that I damaged two 139Cs that could not be repaired. In the case of the 510, I was able to repair it. One goes to the recycle, the other lives to run another test.
Yet another edit to my table at:
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2100013/#msg2100013
Added the Mestek DM91A and the UT139C.
The UT139C comes really close to the ICL7106. Interestingly, the backlight of these two is really low power.
Yet another edit to my table at:
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2100013/#msg2100013
Added the Mestek DM91A and the UT139C.
The UT139C comes really close to the ICL7106. Interestingly, the backlight of these two is really low power.
Curious how nom. current was measured, as I noticed current draw varies by what measurement setting the multimeters is in, with highest draw usually happening in resistance, diode test or continuity modes.
Yet another edit to my table at:
https://www.eevblog.com/forum/testgear/hear-kitty-kitty-kitty-nope-not-that-kind-of-cat/msg2100013/#msg2100013
Added the Mestek DM91A and the UT139C.
The UT139C comes really close to the ICL7106. Interestingly, the backlight of these two is really low power.
IMO, non-autoranger's need separate power switches. On the 133A, common functions are 4-6 clicks away from OFF.. FAIL!!
There is another alternative to Mestek DM91A but with less resolution counts ( 6000) , the Uni-t 133A which is a compact true-rms meter witn NCV:
http://www.uni-trend.com/index.php?m=content&c=index&a=show&catid=172&id=192
It costs around 30E on local market with shipping + 2Y waranty and should be cheaper on other market platforrms
IMO, non-autoranger's need separate power switches. On the 133A, common functions are 4-6 clicks away from OFF.. FAIL!!That's the model 133B you're refering, the 133A is automatic.
Stupid Uni-T does no favours in completely confusing their product families.
How is anybody supposed to buy a Uni-T if they know that there's two or three identical-looking variants out there but some don't have any input protection inside?
The uni-t 136C looks like a compact multimeter , two off positions , simple switch ( not like the 133A here HZ in the mV, bugger ), there is some space that could fit more protection . One of the fuse is glass and other is ceramic on the older picture, which may lead that the original has been tested (just kidding) A little bit of flux residue is also present, near the push buttons. Nice digits (Edit)